Solar cells are well known. A common form of such a cell comprises a wafer of P-type silicon having diffused into one side thereof a doping material such as phosphorus to create a thin N-type silicon layer in the region of the diffusion. This creates a P-N junction near the surface. The action of light directed on such a surface creates a voltage in the region of the junction in a well known manner. In order to utilize the power thus generated, contact must be made to the P-type silicon and also to the N-type silicon, and both contacts must be connected through an external circuit. Such contacts are made by depositing a metal coating on the P-type layer, and one on the opposite side, viz. the N-type layer. Such coatings are commonly referred to as metallizations.
In order for photovoltaic (solar) cells to compete economically as energy sources, reduction in both materials costs and fabrication costs is essential. Cell metallizations constitute a significant portion of total systems costs because they are generally based on expensive palladium and silver compositions applied by cost intensive vacuum deposition techniques. There is a need for metallizations comprised of inexpensive base metals which can be applied economically by thick film techniques and assembled reliably by soldering.